Propeller amd process osi making the same



S. HEATH.

PROPELLER AND PROCESS OF MAKING THESAMEM APPLICATION HLED SEPT-25. *917.

Patented Dec. 23, 1919.

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SPENCER HEATH,

0F BALTIMORE, MARYLAND.

PEUFELLEB. AND PROCESS OF MAKING THE SAME.

Specification of Letters Patent.

Patented ec. 23, 1%19.

Application filed September 25. 1917. serial Ito. 193,131.

To all whom it may concern:

Be it known that I, SPENCER HEATH, a citizen of the United States, residing at Baltimore, State of Maryland, have invented new and useful Improvements in Pro pellers and Processes of Making the Same, of which the following is a specification.

This invention relates to screw propellers and has particular reference to screw propellers built up by connecting together several layers or laminations of wood or similar material and then carving the resultant structure to its requisite form and size.

The object of the invention is to produce a propeller in Whichthe several structural parts shall be most favorably disposed and related each to the other in a Way to pro duce the utmost strength, rigidity and resistance to wear in the finished product.

A further object is to produce a propeller in which there shall be exposed no end grain of the material or end joints of laminations elsewhere than at the extreme end of the propeller blade.

A further object is to produce a propeller in which the laminations forming the interior portions will be of light weight material while the outside laminations are of heavier and more durable material arranged to receive the principal stresses and resist a greater amount of wear.

With the above objects in view, and with other objects that will appear, I have invented the improvements described in this specification and illustrated by aid of the annexed drawings forming a part hereof and in which:

Figure 1 is an elevation of a propeller constructed in accordance with this invention.

Fig. 2 is a plan view of the same.

Fig. 3 is a section on the line 33 of Figs. 1 and 2.

Fig. 4 is a section on the line 4t-4 of Figs. 1 and 2.

Fig. 5 is a section on the line 55 of Figs. 1 and 2.

Fig. 6 is an elevation of the end portion of a propeller embodying the invention in a modified or alternative form.

The propeller is built up in laminations lying flat in their plane of rotation about the axis 1212 and numbered 1 to l on the drawings, but a greater or less number of laminations may be employed. In the practice of the invention the method is first to prepare and combine the members 2, 3, l, 5 and 6 in the relative position and arrangement shown, the ends of these laminations when thus combined being of full thickness as shown by the dotted lines as at 8 in Figs. 1 and 6.

After the interior laminations have been prepared and glued, the portions indicated by the dotted lines 8 at the ends of the laminations are removed by planing down the top and bottom sides of the unfinished propeller, thus preparing a smooth unbroken surface upon which to affix the lamination 1 on the bottom of the uncompleted structure and a similar surface at the top of the unfinished structure to receive the lamination numbered 7. I

As illustrated in Fig. 1, the top and b0ttom of the unfinished structure may both be prepared before the aflixing of either of the outer laminations and both of these laminations 1 and 7 may then be glued at the same time. In this mode one or more of the interior laminations (as 3 and i) are permitted to extend the full length of the propeller blade, having their extreme end portions considerably reduced in thickness and disposed immediately between the end portions of the outer laminations 1 and 7 In the alternative method of Fig. 6, the outer lamination 1 is first applied to the bottom portion of the uncompleted propeller and then the upper portion of the uncompleted propeller is prepared by removing a portion of the end of laminatlon 1, as indicated by the dotted lines 9, in addition to removal of dotted portions 8 of interior laminations i, 5 and 6. The top side of the uncompleted propeller is now ready to receive the outer lamination 7 which in this form will be glued directly to the end of lamination l where prepared by removal of the dotted portion at 9. In this mode of construction laminations 8 and d terminate at points somewhat short of the extreme end of the propeller which end portion is now formed solely by the material furnished by the union of laminations 1 and 7.

As described above. the lamination 7 is afhxcd subsequently to lamination 1 but this order may be reversed Without material change in theresult.

In the practice of the invention it is preferred that the interior laminations '2, 3, 4, 5 and 6 shall be of relatively light weight material such as mahogany or sprueewhile one or both of the outer laminations 1 and 7 are of oak or other stronger and 'more durable material.

Another feature is that either or both the v outer laminations 1 and 7 may, before being has been had to only one blade of the propeller. It is, of course, to be understood that the same applies to the opposite blade which is shown only in part up to the broken line 10. In the case of two-bladed propellers all or part of the laminations may extend continuously from blade to blade of the propeller or they may be spliced or joined at the hub or center of the propeller in any preferred manner, or as shown in Letters Patent No. 1,006,209, dated October 17th, 1911, and No. 1,081,612, dated December 16th, 1913, granted to this applicant. For three-bladed propellers it is, of course, necessary to join all laminations in the hub, either by butt joints or by long slanting scarfs in which the hub ends of the laminations are reduced to a thin edge, as illustrated and described in Letters Patent No. 1,006,209 and No. 1,081,612, above referred to.-

A particular advantage of the described method and construction is that the resulting propeller blade has the general form of an A-truss in which the two outer members 1 and 7 take the greater part of stress and wear, are of practically continuous and unbroken fiber throughout their length and are brought toward each other or together at the end of the blade to secure that strength and stability which is characteristic of the triangular form. In this view the interior laminations may be considered as forming the web or filler portion to withstand. the minor stresses. Further, the laying of the continuous outer laminations over the planed down ends of the interior laminations effectually covers and protects all the end wood and very thin end joints of the interior members.

What I claim is:-

1. The method of propeller construction which consists in preparing and assembling with glue interior laminations forming an.

incomplete propeller structure, preparing the incomplete structure b removal of portions of the ends of its laminations to form a continuous unbroken surface and atlixing an outer lamination to the surface thus prepared.

2. The method of propeller construction which consists in preparing and assembling with glue interior laminations forming an incomplete propeller structure, preparing the incomplete structure by removal of portions of the ends of its laminations to form a continuous unbroken surface and atlixing an outer lamination to the surface thus pre pared and removing surplus material from the thus completed propeller structure.

8. The method of propeller construction which consists in preparing and assembling with glue interior laminations forming an incomplete propeller structure, preparing the incomplete structure by removal of portions of the ends of its laminations to form continuous unbroken surfaces on opposite sides of the incomplete structure and ailixing outer laminations bent toward each other and extending to the end of the propeller blade.

4. The method of propeller construction which consists in preparing and assembling with glue interior laminations forming an incomplete propeller structure, preparing the incomplete structure by removal of portions of the ends of its laminations to form continuous unbroken surfaces on opposite sides of the incomplete structure and atfixing outer laminations bent toward each other and extending to the end of the propeller blade, and removing surplus material from the thus completed propeller structure.

5. The method of propeller construction which consists in preparing and assembling with glue interior laminations forming an incomplete propeller structure, preparing the incomplete structure by removal of portions of the ends of its laminations to form a continuous unbroken surface, preparing an outer lamination by steaming and bending to conform to the curve of the edge of the propeller, and aflixing the bent outer lamination to the surface thus prepared.

6. A propeller structure comprising an in terior portion formed of laminations of unlike lengths having their ends dressed down to a continuous unbroken surface on each of the two opposite sides of said interior portion, and an exterior portion formed of two outer laminations affixed to said surfaces and bent, toward each other and extending to the end of the propeller structure.

7. A propeller structure comprising an in terior portion farmed of laminations of un- Eat in the planes of their heir ends dressed down face on each of .d interior per tion, and an exterior portion formed of two outer laminations affixed to said surfaces and bent toward each other and extending to the end of the propeller structure.

. 8. A propeller structure comprising an assembly of laminations of unlike lengths lying in the plane of rotation, the ends of the 'laminations being dressed down to a continuous unbroken surface, and a further lamination affixed to the surface thus prepared.

9. A propeller structure comprising an assembly of laminations of unlike lengths lying in the plane of rotation, the ends of the laminations being dressed down to a con tinuous unbroken surface, and a further lamination extending along the propeller and aihxed to the surface thus prepared.

10. A propeller structure comprising an assembly of laminations of unlike lengths lying in the plane of rotation, the ends of the laminations being dressed down to a continuous unbroken surface, and a further lamisaid further lamination being bent to conform to the curved edge of the propeller.

11. A propeller structure comprlsing an assembly of laminations of unlike lengths lying in the plane of rotation, the ends of the laminations being dressed down to a continuous unbroken surface, and a further lamination extending to the end of the propeller and aflixed to the surface thus prepared, said further lamination being bent to conform tothe curved edge of the propeller. 12. A propeller structure comprising an interior portion formed of laminations of unlike lengths lying in the plane of rotation and havingtheir ends dressed down to a continuous unbroken surface on each of the two opposite sides of said interior portion and an exterior portion formed of two laminations extending to and forming the end of the propeller and afiixed to said surfaces and to each other. V

In testimony whereof l[ have hereunto set sienuonn rrnnrn.

my hand. nation axed to the surface thus prepared, I 

